ARM: ensure initial page tables are setup for SMP systems
Mapping the same memory using two different attributes (memory
type, shareability, cacheability) is unpredictable. During boot,
we encounter a situation when we're updating the kernel's page
tables which can lead to dirty cache lines existing in the cache
which are subsequently missed. This causes stack corruption,
and therefore a crash.
Therefore, ensure that the shared and cacheability settings
matches the configuration that will be used later; this together
with the restriction in early_cachepolicy() ensures that we won't
create a mismatch during boot.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 194737d..70f75d2 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -32,8 +32,10 @@
#ifndef CONFIG_SMP
#define TTB_FLAGS TTB_RGN_WBWA
+#define PMD_FLAGS PMD_SECT_WB
#else
#define TTB_FLAGS TTB_RGN_WBWA|TTB_S
+#define PMD_FLAGS PMD_SECT_WBWA|PMD_SECT_S
#endif
ENTRY(cpu_v6_proc_init)
@@ -222,10 +224,9 @@
.long 0x0007b000
.long 0x0007f000
.long PMD_TYPE_SECT | \
- PMD_SECT_BUFFERABLE | \
- PMD_SECT_CACHEABLE | \
PMD_SECT_AP_WRITE | \
- PMD_SECT_AP_READ
+ PMD_SECT_AP_READ | \
+ PMD_FLAGS
.long PMD_TYPE_SECT | \
PMD_SECT_XN | \
PMD_SECT_AP_WRITE | \